What VPN companies said about port forwarding. This works well for your home, but it doesn't work well for VPN's where multiple users would want to open the same port for the same reasons. NAT
Jun 15, 2020 What is a VPN Port? - Definition from Techopedia The number and type of VPN ports utilized depends on the protocol used. For example, the PPTP protocol uses TCP port number 1723 to create a connection to IP port 47 Generic Routing Encapsulation (GRE) for packet encapsulation. How do I enable port forwarding on my VPN? - Knowledgebase
About Azure Point-to-Site VPN connections | Microsoft Docs
May 20, 2003 How to open a port in the firewall on Windows 10 May 31, 2018
Open port forwarding using a VPN NAT firewall can still leave the port open. This means that not port forwarding via a VPN is usually safer as compared to port forwarding. However, in most cases, port forwarding is still very safe. Take note that port forwarding via a VPN service will ensure your connections remain well encrypted by a VPN.
Which ports do you need to open on a firewall to allow To enable VPN tunnels between individual host computers or entire networks that have a firewall between them, you must open the following ports: PPTP. To allow PPTP tunnel maintenance traffic, open TCP 1723. To allow PPTP tunneled data to pass through router, open Protocol ID 47. L2TP over IPSec. To allow Internet Key Exchange (IKE), open UDP 500. What port does VPN use? Below is a list of some common VPN protocols and the ports that they use: PPTP (Point-to-Point Tunneling Protocol) – This protocol uses port 1723 TCP. L2TP (Layer Two Tunneling Protocol) – This protocol uses port 1701 TCP, Port 500 UDP, and port 4500 UDP.